Seroquel patent row continues

The legal tug of war over the right to sell generic versions of Seroquel (quetiapine) tablets continues. In the latest round, a US court has ruled that the patent for the extended release formulation, sold by AstraZeneca as Seroquel XR tablets, is valid and has been infringed by several generic manufacturers. AstraZeneca is now facing generic erosion of its blockbuster Seroquel brand - the patent for quetiapine expired a few days ago. But the patent for the Seroquel XR formulation, which patients take less frequently compared with the original formulation, offers the possibility of maintaining some exclusivity until 2017. Only a week ago, AstraZeneca lost out in a UK court, which ruled the patent invalid. The Seroquel brand is an important part of the AstraZeneca portfolio - it generated $4.3 billion (£2.7 billion) in global sales in 2011.